Note: the "reserved" and "disabled" pairs do not actually map to aphysical pair of pins, nor GPIO regs and shouldn't be initialized or used.Fixing this is left for a later patch.

This bug has not been noticed for two reasons: 1) "gmbus" mode is currently disabled - all transfers are actually using "bit-bang" mode which uses the GPIO port 5 (the "HDMI/DPD CTLDATA/CLK" pair), at register 0x5024 (defined as GPIOF i915_reg.h). Since this is the correct pair of pins for HDMI1, transfers succeed.

2) Even if gmbus mode is re-enabled, the first attempted transaction will fail because it tries to use the wrong ("Reserved") pin pair. However, the driver immediately falls back again to the bit-bang method, which correctly uses GPIOF, so again, transfers succeed.

However, if gmbus mode is re-enabled and the GPIO fall-back mode isdisabled, then reading an attached monitor's EDID fail.